added imap daemon

+1999-10-11  Sean 'Shaleh' Perry  <shaleh@debian.org>
+
+	* added my imap code -- PLEASE DO NOT TOUCH
+
 1999-10-10  Jeff Bailey  <jbailey@cr499794-a.crdva1.bc.wave.home.com>
 
 	* THANKS: New file

+#include "capability.h"
+
+STATUS imap_capability(Command *command) {
+
+	if( command->args )
+		return BAD;
+
+	fprintf(output, "* CAPABILITY IMAP4rev1\r\n");
+
+	return OK;
+}

+#ifndef _MY_IMAP_CAPABILITY
+#define _MY_IMAP_CAPABILITY
+
+#include "imap.h"
+
+STATUS imap_capability(Command *command);
+
+#endif

+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "command.h"
+
+Command* parse_command(char *string) {
+
+	size_t len, tmp;
+	Command *command;
+
+	if( string == NULL )
+		return NULL;
+
+	command = malloc(sizeof(Command));
+	memset(command, '\0', sizeof(Command));
+
+	len = strcspn(string, " ");
+	if( len > 0 ) {
+		tmp = strcspn(string, "\r\n");
+		string[tmp] = '\0';
+		strncpy(command->tag, string, len > 15 ? 15 : len);
+	} else {
+		strcpy(command->tag, "gibberish");
+		return command;
+	}
+
+	tmp = len;
+	++tmp; /* skip space char */
+	len = strcspn(string + tmp, " ");
+	if( len > 0 )
+		strncpy(command->cmd, string + tmp, len > 15 ? 15 : len);
+	else {
+		strcpy(command->cmd, "gibberish");
+		return command;
+	}	
+	/* args is the rest of the string */
+	command->args = string + len + tmp + 1;
+
+	if( command->args[0] == '\0' ) /* no args */
+		command->args = NULL;
+
+	return command;
+}
+
+void free_command(Command *command) {
+
+	free(command);
+}

+#ifndef _MY_IMAP_COMMAND
+#define _MY_IMAP_COMMAND
+
+#include "imap_types.h"
+
+Command *parse_command(char *string);
+void free_command(Command *command);
+
+#endif

+#ifndef _MY_IMAP
+#define _MY_IMAP
+
+#include <stdio.h>
+#include <syslog.h>
+
+#include "imap_types.h"
+
+FILE *input;
+FILE *output;
+
+/* current server state */
+STATES state;
+
+#endif

+#ifndef _MY_IMAP_COMMANDS
+#define _MY_IMAP_COMMANDS
+
+#include "capability.h"
+#include "login.h"
+#include "logout.h"
+#include "noop.h"
+
+#endif

+#ifndef _MY_IMAP_TYPES
+#define _MY_IMAP_TYPES
+
+/* possible server states */
+enum _STATES {NON_AUTH, AUTH, SELECTED, LOGOUT};
+
+/* imap command status codes */
+enum _STATUS {BAD, NO, OK};
+
+typedef enum _STATES STATES;
+typedef enum _STATUS STATUS;
+
+typedef struct _Command {
+	char tag[16]; 
+	char cmd[16];
+	char *args;
+} Command;
+
+#endif

+#define _XOPEN_SOURCE
+#include <unistd.h>
+#include <ctype.h>
+#include <pwd.h>
+#include <shadow.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "login.h"
+
+STATUS imap_login(Command *command) {
+
+	char user[256];
+	char *pass;
+	struct passwd *pw;
+	struct spwd *shadow;
+	size_t len;
+
+	if( state != NON_AUTH )
+		return BAD;
+	if( command->args == NULL )
+		return BAD;
+
+	len = strcspn(command->args, " ");
+	if( len == 0 || len > 255 )
+		return BAD;
+	memset(user, '\0', 256);
+	strncpy(user, command->args, len);
+	pass = command->args + len;
+	++pass; /* skip the space */
+	if( isspace(pass[0]) )
+		return BAD;
+	pw = getpwnam(user);
+	if ( pw == NULL ) {
+		syslog(LOG_WARNING, "invalid user: %s\n", user);
+		return NO;
+	}
+	if( strcmp(pw->pw_passwd, crypt(pass, pw->pw_passwd)) ) {
+		shadow = getspnam(user);
+		if( shadow == NULL ) {
+			syslog(LOG_WARNING, "invalid user: %s\n", user);
+			return NO;
+		}
+		if( strcmp(shadow->sp_pwdp, crypt(pass, shadow->sp_pwdp)) ) {
+			syslog(LOG_WARNING, "invalid user: %s\n", user);
+			return NO;
+		}
+	}
+	memset(pass, '\0', sizeof(pass)); /* paranoia */
+	state = AUTH;
+	syslog(LOG_INFO, "user: %s, logged in\n", user);
+	return OK;
+}

+#ifndef _MY_IMAP_LOGIN
+#define _MY_IMAP_LOGIN
+
+#include "imap.h"
+
+STATUS imap_login(Command *command);
+
+#endif

+#include "logout.h"
+
+STATUS imap_logout(Command *command) {
+
+	if( command->args )
+		return BAD;
+
+	/* finish everything */
+
+	fprintf(output, "* BYE IMAP4rev1 terminating connection\r\n");
+#ifdef STATISTICS
+	statistics();
+#endif
+
+	state = LOGOUT;
+
+	return OK;
+}

+#ifndef _MY_IMAP_LOGOUT
+#define _MY_IMAP_LOGOUT
+
+#include "imap.h"
+
+STATUS imap_logout(Command *command);
+
+#endif

+#include <grp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "imap.h"
+#include "imap_commands.h"
+#include "command.h"
+#include "readline.h"
+
+static void init(void);
+static int mainloop(void);
+static void cleanup(void);
+static void greeting(void);
+static STATUS action(Command *command);
+
+/* state the server is in */
+STATES state = NON_AUTH;
+
+FILE *input = NULL;
+FILE *output = NULL;
+
+/* output strings, maps STATUS to strings */
+static char *status_word[3] = {"BAD", "NO", "OK"};
+static char *status_code[3] = {"invalid", "failed", "completed"};
+
+
+int main(int argc, char *argv[]) {
+
+	input = stdin;
+	output = stdout;
+
+	init();
+
+	greeting();
+
+	mainloop();
+
+	cleanup();
+	
+	fclose(input);
+	fclose(output);
+
+	return 0;
+}
+
+static void init(void) {
+
+	struct group *gr;
+
+	gr = getgrnam("mail");
+	if( gr == NULL )
+		exit(-1);
+	if( setgid(gr->gr_gid) == -1 )
+		exit(-1);
+	openlog("GNU IMAP4", LOG_PID, LOG_MAIL);
+	if( output == stdout )
+		setvbuf(output, NULL, _IOLBF, 0);
+}
+
+static void cleanup(void) {
+	closelog();
+}
+
+static void greeting(void) {
+
+	fprintf(output, "* OK IMAP4rev1 Service Ready\r\n");
+}
+
+static int mainloop(void) {
+
+	char *client_string;
+	Command *command;
+	STATUS status;
+
+	while( (client_string = read_a_line(input)) != NULL ) {
+		command = parse_command(client_string);
+		status = action(command);
+
+		fprintf(output, "%s %s %s %s\r\n", command->tag, status_word[status],
+				command->cmd, status_code[status]);
+
+		free_command(command);
+		free(client_string);
+
+		if( state == LOGOUT ) /* all done, let's go */
+			break;
+	}
+
+	return 1;
+}
+
+STATUS action(Command *command) {
+
+	if( strcasecmp(command->cmd, "capability") == 0 ) {
+		return imap_capability(command);
+	}
+	else if( strcasecmp(command->cmd, "noop") == 0 ) {
+		return imap_noop(command);
+	}
+	else if( strcasecmp(command->cmd, "logout") == 0 ) {
+		return imap_logout(command);
+	}
+	else if( strcasecmp(command->cmd, "login") == 0 ) {
+		return imap_login(command);
+	}
+
+	return BAD;
+}

+#include "noop.h"
+
+STATUS imap_noop(Command *command) {
+
+	if( command->args )
+		return BAD;
+
+	fprintf(output, "* OK XSTATE %d\r\n", state);
+
+	return OK;
+}

+#ifndef _MY_IMAP_NOOP
+#define _MY_IMAP_NOOP
+
+#include "imap.h"
+
+STATUS imap_noop(Command *command);
+
+#endif

+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef COUNT
+#define COUNT 128 /* safe, middle of the road value */
+#endif
+
+/**
+ * reads a single line from *stream
+ * max line length is max size of size_t
+ * 
+ * PRE: stream is an open FILE stream
+ * POST: returns an allocated string containing the line read, or errno is set
+ *
+ * note, user must free the returned string
+ **/
+char *read_a_line(FILE *stream) {
+
+	char *line = NULL;
+	size_t buffsize = 0; /* counter of alloc'ed space */
+
+	if( feof(stream) ) { /* sent a bum stream */
+		errno = EINVAL;	
+		return NULL;
+	}
+
+	do {
+		if ((line = realloc(line, buffsize + (sizeof(char) * COUNT))) == NULL) {
+			errno = ENOMEM;
+			return NULL;
+		}
+		if( fgets(line + (buffsize ? buffsize - 1 : 0),COUNT,stream) == NULL ) {
+			if( buffsize == 0 ) {
+				errno = EINVAL;
+				return NULL; /* eof w/ nothing read */
+			}
+			break; /* read a line w/o a newline char */
+		}
+		buffsize += COUNT;
+	} while( (strchr(line, '\n')) == NULL );
+
+	return line;
+}

+#ifndef _MY_read_a_line__
+#define _MY_read_a_line__
+
+char* read_a_line(FILE *stream);
+
+#endif